Heroin (diacetylmorphine) is an opioid developed as an antitussive agent during the late nineteenth century. Heroin abuse soon became a problem and continues to be so now, more than a century later. Following ingestion, heroin is quickly metabolized to 6-monoacetyl morphine (6-MAM) and then to morphine, which in turn undergoes extensive metabolism.

Acetylcodeine is a synthetic byproduct present in street heroin but not in pharmaceutical diacetylmorphine, which is used in heroin-assisted treatment for opiate dependent drug users. Acetylcodeine (AC) was investigated as a urinary biomarker for detection of illicit heroin use. Detection of acetylcodeine could play an important role in determining if addicts enrolled in heroin maintenance programs were supplementing their supervised diacetylmorphine doses with illicit heroin.

The problem presently unsolved by the prior art is the unavailability of antibodies which will allow detection of 6-MAM or 6-MAC as markers of heroin abuse without interference from other opiates such as morphine or codeine which may derive from legitimate medical prescriptions, e.g., cough syrup, or even diet, e.g., poppy seeds. The present invention provides chemical analogs useful in development of antibodies that recognize 6-MAM and 6-MAC and in production of conjugates useful in immunoassay methods for detection of 6-MAM and 6-MAC.